The Discovery of Reserpine - Research Paper Example

Reserpine Introduction Reserpine is one of the Indole alkaloids contained in a plant d Rauwolfia serpentina benth common in India (Dewick 353). It was first isolated by E. Schlittler and his co-scientists during the year 1952 (Woodward, Bader, Bickel, Frey and Kierstead 2023) and had gained its name in history as it was considered as the first tranquilizer ever discovered (Basu, Pereira, and Aitchison 238). However, chlorpromazine and other ant-psychotics have replaced it in its place in psychopharmacology on the present days. On the other hand, reserpine is still indicated for several clinical conditions, especially as an anti-hypertensive agent, due to its several chemical components, and the actions that it causes on neurotransmitters. The Discovery of Reserpine Reserpine was first called by the Indian people as sarpagandha. It was one of the components found in Rauwolfia serpentina benth, a climbing shrub named after in honor of its discoverer Leonard Rauwolf who was the first one to include the plant in his botanical studies (Healey 101).The Indian society found many use in sarpagandha, or reserpine. It was applied in treating fever, vomiting, snake bites, insomnia and insanity, among others. They have had also used it in inducing sleep to children utilizing low doses of the plant and as a treatment for insanity in high level of doses (Healey 102). Because of its apparent use in treating a number of ailments gaining its significance in the field of medicine, scientists subjected rauwolfia for research and chemical experimentations. In the year 1952, Healey noted that E. Schlittler, Hugo Bein and other Swiss scientists working for Ciba laboratories (presently Novartis) first isolated and were able to identify the structure of reserpine that was considered as the most important evidence in clarifying the actions of its plant source (103). The drug gained more popularity during the 1960s and 1970s. However, because its depression effect (Leyton, Kwai Pun, Benkelfat, and Young 464) caused by its inhibition of serotonin’s accumulation (Hudlicky and Reed 541), the use of reserpine in psychiatric cases declined. With the same reason, its employment is controlled nowadays even with its proven action in the adrenergic neurons that can cause therapeutic effect versus hypertension (Williams and Lemke 572). Reserpine and Its Physical Properties Reserpine is chemically known as methyl 18β-hydroxy-11, 17 α-dimethoxy-3β, 20α-yohimban-16β-carboxylate 3,4,5-trimethoxybenzoate (ester) (“Reserpine” DailyMed). Although it generally appears with a yellowish color because of its sensitivity to light, reserpine is actually a white crystalline powder. Its melting point is about 270°C and it is odorless and almost tasteless (Szasz and Budvari-Barany 139). Its solubility to acetone, benzene and alcohol, on the other hand, is poorer compared to chloroform and acetic acid with which it is freely soluble. Moreover, reserpine’s basicity is slightly far from the center of basicity which is 4. Its pH level lies between 6 and 7.5; thus, rendering the name alkaloid. Reserpine gives off 3,4,5-trimethoxybenzoic acid and an amino acid which we called reserpenic acid when it is hydrolyzed with a diluted alkaline solution (Neuss, Boaz, and Forbes 2463). When it is reduced using lithium aluminum hydride, moreover, Neuss, Boaz and Forbes enumerated that “3,4,5-trimethoxybenzyl alcohol and an amino alcohol, named reserpenic alcohol” can be obtained (2463). These processes led to the formulation of its empirical and structural formulas. Its empirical formula is C₃₃H₄₀N₂₀₉ (Barbalace); while its structural formula is the following: Reserpine has a molecular weight of 608.69 g/mol (“Reserpine” Drugs.com) and it is a diester. It has two ester groups: the carbomethoxyl and hydroxyl groups, which are “esterified with 3,4,5-trimethoxybenzoic acid” (Klohs, Draper, Keller, and Petracek 4867). Reserpine Synthesiss There are already a number of ways in synthesizing reserpine, all of which were primarily based on Robert Burns Woodward and company’s first total synthesis of the compound in 1956. Some of the names that invented these ways were Stephen F. Martin and company of the University of Texas (Martin, Grzejszczak, Rueeger, and Williamson 4072); B. Pearlman of Columbia (Michigan State University); and the latest developers, Gilbert Stork and company of Columbia University (Stork, Tang, Casey, Goodman, and Toyota 16255). Although there appeared many options of synthesizing reserpine, Woodward’s synthesis also currently serves as the basis of the drugs production (“Facts About Reserpine”). The Stork Synthesis of (-)-Reserpine. In the present available ways of synthesizing reserpine, Gilbert Stork’s synthesis now holds most of the attention. Stork’s synthesis is told to “illustrate the power of chiral induction for the kinetic establishment of distal stereocenters” (Taber). Aldehyde tosylate (2) was condensed together with 6-methoxytryptamine (1), which in turn obtained reserpine at the end of the process (3). According to Douglas Taber, Stork derived aldehyde tosylate through a series of additions, reductions, oxidations, and mythelations of certain products. It is to be distinguished that instead of using Diels-Alder cycloadditon, Stork used two sequential Michael additions in the first process making up aldehyde tosylate. Nonetheless, both Diels-Alder and Michael additions held same results. After achieving aldehyde tosylate, it was combined 6-methoxytryptamine and had to undergo combination of cyanide ion and stirring at room temperature in an aqueous hydrochloride that eventually provided the synthesis of reserpine (Taber). The Uses of Reserpine Reserpine induces differentiated effects, depending on its concentration levels. The most popular use of the chemical is applied in brain chemistry; this has become the basis of its psychopharmacologic use. Moreover, it has also proven its importance in maintaining the level of blood pressure by keeping it below hypertensive levels. The drug is told to cause prevention of accumulation of amines in the secretory vesicles, specifically norepinephrine. It also has the same effect to serotonin. The chemical components of reserpine do this by inhibiting the “ATP-dependent monoamine transport into the adrenal medullary chromaffin granules, adrenergic synaptic vesicles and the serotonin-containing granules of platelets” (Zallakian, Knoth, Metropoulos, and Njus 1051). As a result, norepinephrine and serotonin is released, making it available for the monoamine oxidase degradation. As monoamine oxidase deaminates the norepinephrine and serotonin, the two catecholamine functions are inhibited (Kopin and Axelrod). In high and uncontrolled levels, reserpine would cause severe depression in patients who are taking it. As for the blood pressure control, on the other hand, the antihypertensive action of reserpine is still a result of its ability “deplete catecholamines from peripheral sympathetic nerve ending” (Kar 715) that further results to the creation of an adrenergic neuronal blockade as catecholamine granules are decreased in the postganglionic sympathetic neurons; and thus, lowering of the arterial blood pressure. Reserpine, conversely, does not produce such direct effects as it causes such actions for it was found to be completely eliminated from the body just a few hours after it was administered. Nonetheless, such reactions can be accounted through the “central effects” of reserpine has upon the neurochemistry of those who have taken it in which can cause marked change in the brain serotonin and norepinephrine among others. Conclusion Reserpine had served well in the field of science as it functions as a tranquilizing and antihypertensive agent upon its discovery in 1952 and was one of the first antipsychotic drugs with significant use in neuroscience as it causes indirect yet very significant effects on brain chemistry. Because it was found to produce toxic consequences when high doses are administered, however, the consumption of the drug has declined over the years. Medical practitioners must put extra care in prescribing the drug as it affects several important chemical neurotransmitters become affected upon its consumption. It must, furthermore, be subjected to more critical chemical studies and on-going researches to find a way around and keeping its significant use in the medical field despite its negative effects. It can be possible since today’s science and technology already has the power to do so. Works Cited Barbalace, Kenneth L. “Reserpine.” Chemical Database. J. K. Barblace, Inc., n.d. 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The Characterization of Reserpine and Its Hydrolysis Products.” Journal of the American Chemical Society 75.19 (1953, October 5): 4867. Print. Kopin, Irwin J., and Julius Axelrod. “The Role of Monoamine Oxidase in the Release and Metabolism of Norepinephrine.” WileyInterScience. John Wiley & Sons, n.d. Web. 22 Apr. 2010. . Leyton, Marco, Valerie Kwai Pun, Chawki Benkelfat, and Simon N. Young. “A New Method for Rapidly and Simultaneously Decreasing Serotonin and Catecholamine Synthesis in Humans.” Journal of Psychiatry & Neuroscience 28.6 (2003): 464. Print. Martin, Stephen F., Slawomir Grzejszczak, Heinrich Rueeger, and Sidney A. Williamson. “Total Synthesis of (.+-.)-Reserpine.” Journal of the American Chemical Society 107.13 (1985 June): 4072. Print. Michigan State University. “Principles of Organic Synthesis.” Synthesis. Michigan State University Department of Chemistry, n.d. Web. 12 Apr. 2010. . Neuss, Norbert, Harold E. Boaz, and James W. Forbes. “Rauwolfia Serpentina Alkaloids. I. Structure of Reserpine.” Journal of the American Chemical Society 76.9 (1954): 2463. Print. “Reserpine.” DailyMed. U.S. National Library of Medicine, n.d. Web. 12 Apr. 2010. . “Reserpine.” Drugs.com. Drugs.com, n.d. Web. 12 Apr. 2010. . Stork, Gilbert, Peng Cho Tang, Michael Casey, Burton Goodman, and Masahiro Toyota. ”Regiospecific and Stereoselective Syntheses of (±)-Reserpine and (−)-Reserpine.” Journal of the American Chemical Society 127. 46 (2005, November 1): 16255-16262. Print. Szasz, Gyorgy, and Zsuzsanna Budvari-Barany. Pharmaceutical Chemistry of Antihypertensive Agents. Florida, USA: CRC Press, 1991. Print. Taber, Douglas. “Total Synthesis: The Stork Synthesis of (-)-Reserpine.” Organic Chemistry Portal. Organic-chemistry.org, n.d. Web. 12 Apr. 2010. . Williams, David A., and Thomas L. Lemke. Foye’s Principles of Medicinal Chemistry. 5th ed. Philadelphia, MD: Lippincott Williams & Wilkins, 2002. Print. Woodward, Robert Burns, F. E. Bader, H. Bickel, A. J. Frey, and R. W. Kierstead. “The Total Synthesis of Reserpine.” Journal of the American Chemical Society 78.9 (1956, May): 2023. Print. Zallakian, Michael, Jane Knoth, George E. Metropoulos, and David Njus. “Multiple Effects of Reserpine on Chromaffin-granule Membranes.” Biochemistry 21.5 (1982 March): 1051. Print. Read More